Rare variant (genetics)

<p>A rare variant is a <a href="/facts/Mutation/Ee4NnWbY">genetic variant</a> which occurs at low <a href="/facts/Allele_frequency/gRApYaIy">frequency</a> in a population.  Rare variants play a significant role in both complex and <a href="/facts/Mendelian_inheritance/v2038wkl">Mendelian</a> disease and are responsible for a portion of the missing <a href="/facts/Heritability/REQ3CfRe">heritability</a> of complex diseases. The theoretical case for a significant role of rare variants is that <a href="/facts/Allele/8FxCS9KA">alleles</a> that strongly predispose an individual to disease will be kept at low frequencies in populations by <a href="/facts/Purifying_selection/DCkRLqb4">purifying selection</a>. Rare variants are increasingly being studied, as a consequence of <a href="/facts/Exome_sequencing/kTvyt9Nc">whole exome</a> and <a href="/facts/Whole_genome_sequencing/WNuHaU2K">whole genome sequencing</a> efforts. While these variants are individually infrequent in populations, there are many in human populations, and they can be unique to specific populations.  They are more likely to be <a href="/facts/Mutation/Ee4NnWbY">deleterious</a> than common variants, as a result of rapid population growth and weak purifying selection.  They have been suspected of acting independently or along with <a href="/facts/Common_disease-common_variant/23JI0jym">common variants</a> to cause disease states.
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Rare variant (genetics) open-in-new

Rare variant (genetics)